To the five terms of Porphyry, a sixth,—the ‘Individual’—is added, no doubt for the sake of symmetry. Three of these,—Genus, Species, Individual,—are then called Objective Qualifications and three,—Difference, Property, Accident—Abstract or Conceptional Qualifications. The Categories are Genus-conceptions, of which the first is Substance, the other nine denoting its Accidents. The whole system of Concepts is farther developed by a division into species. But besides Division, there are three additional logical methods in use: Analysis, Definition and Deduction. Analysis is the method for beginners, because it permits a knowledge of what is individual. More subtle, however, as disclosing to us what is spiritual,—are Definition and Deduction, the former investigating the essential nature of Species, and the latter that of Genera. The Senses apprise us of the existence of things; but acquaintance with the essence of things is gained by reflection. The information which is conveyed to us by the senses is small, as it were the letters of the alphabet. Of greater importance considerably are the principles of rational knowledge, just as words have more significance than letters; but the most important knowledge of all, lies in the propositions which have been derived from those principles, and which the human mind gains for itself or appropriates, in contradistinction to that knowledge which Nature or the Divine revelation has imparted to it. 7. From God, the highest Being, who is exalted above all distinctions and oppositions both of the Material and the Spiritual, the whole world is derived by the path of Emanation. If now and again a Creation is spoken of, that is only to be understood as a form of adaptation to theological language. The gradation then of the Emanations is exhibited as follows: 1. The Creative Spirit (νοῦς, ʻaql); 2. The Passive Spirit, or the All-Soul or World-Soul; 3. The First Material; 4. The Operative Nature, a power of the World-Soul; 5. The Absolute Body, called also, the Second Material; 6. The World of the Spheres; 7. The Elements of the Sublunary World; 8. The Minerals, Plants and Animals composed of these elements. These then are the eight Essences which,—together with God, the Absolute One, who is in everything and with everything—complete the series of Original Essences corresponding to the nine Cardinal Numbers.